Uncovering the bidirectional relationship between PD and DM

Researchers from Pusan National University have explored the bidirectional relationship between periodontitis (PD) and diabetes mellitus (DM) through single-cell RNA analysis and have discovered a first of its kind immunological explanation for the complex association between PD and DM.

PD is a common condition in individuals with DM, but previous studies concentrating on local immune responses in gingival tissue do not ascertain the systemic immunological relationship. In the new study, led by Dr Yun Hak Kim from Pusan National University, the team analysed peripheral blood mononuclear cells, using single-cell RNA sequencing, from a diverse group that included healthy individuals, PD patients and patients with both PD and type 2 diabetes mellitus (PDDM). In both the PD and PDDM groups they found that the levels of pro-inflammatory cytokines rose in classical monocytes.

Further analysis uncovered the influence of DM on T lymphocyte counts. CD4+ effector T cells demonstrated reduced activation under DM conditions, suggesting a wider systemic impact on immune regulation. Also, in both PD and DM, CD8+ T cells and natural killer (NK) cells had compromised functions, denoting immune changes happening at the cellular level.

Moreover, the RESTIN pathway, which is known for its association with insulin resistance, was intensified in PD and PDDM groups, mostly involving classical monocytes. This indicates a shared intercellular pathway that contributes to the PD-DM relationship. RESTISTIN in the blood of PD patients without underlying diseases shows its role in inflammation and its potential as a therapeutic target to reduce diabetes risk in patients with PD.

Significant immune alterations in patients with both PD and DM emphasises the potential role as PD as a precursor to diabetes. Dr Kim explained: “Leveraging the findings from our research, incorporating supplementary therapies for PD can facilitate glycaemic control and reduce the likelihood of developing DM. Recognising the capacity of PD to impact the susceptibility and handling of DM holds significant implications for healthcare, studies, public health, and holistic welfare of individuals.”

Dr Kim added: “Our study promises to transform our understanding of the complex interplay between these two prevalent health conditions and sheds light on the systemic impact of these conditions offering a potential avenue for targeted interventions.”

This study was published in Clinical and Translational Medicine.